1. Field of the Invention
This invention relates to an ambulatory electrocardiographic apparatus which can detect the electrocardiographic signals from a subject. The signals can be recorded and analyzed without any restraint on the subject for a long period of time. More particularly, the invention relates to an ambulatory electrocardiographic apparatus which is provided with an IC memory card detachable from the main body of the apparatus. With the invention the electrocardiographic signals detected can be analyzed in accordance with a program stored in the IC memory card; the results of the analysis, together with the electrocardiographic signals, can be stored in the IC memory card; and these data can be dispensed on a display means of the main body of the apparatus.
2. Description of the Prior Art
In conventional ambulatory electrocardiographic apparatuses, the electrocardiographic signals detected and the results of the analysis thereof are first stored in a storage medium such as a magnetic tape mounted on the main body of the apparatus. When the recording is complete, the storage medium is dismounted from the main body and then set on an analyzing unit which is provided separately from the main body. The data stored in the storage medium is analyzed in accordance with a program for analysis stored in the analyzing unit. The results of the analysis are given on a CRT display unit or a printer connected to the analyzing unit.
In the Japanese Laid-Open Patent Publications No. 49-20981, No. 49-27087, and No. 51-90784, there are disclosed compact, light-weight ambulatory electrocardiographic apparatuses in which recording and replaying of electrocardiographic signals are performed in the same mechanism by the use of a magnetic tape as the storage medium. Japanese Laid-Open Patent Publication No. 58-19229 discloses an ambulatory electrocardiographic apparatus which is capable of recording for a long period of time by the use of a detachable magnetic bubble memory as the storage medium. In this apparatus, the electrocardiographic signals detected are compressed and stored in the bubble memory. The Japanese Laid-Open Patent Publication No. 59-222129 discloses an ambulatory electrocardiographic apparatus in which an IC memory is utilized as the storage medium. In this apparatus, different patterns of the electrocardiographic waveform detected are all marked with symbols and registered in a pattern table, so that memory capacity required for recording electrocardiographic signals for a long period of time can be considerably reduced by recording only the symbols with respect to the electrocardiographic waveform of the different patterns. Japanese Patent Application No. 63-65246 discloses an ambulatory electrocardiographic apparatus comprising a memory means, a memory control means, and a dataholding control means, wherein the electrocardiographic data are renewed and stored sequentially with time, so that only the electrocardiographic data necessary for analysis can be obtained with high efficiency and reliability.
When analyzing electrocardiographic signals, it is desirable to change the methods for analyzing and recording the electrocardiographic signals depending upon the kind of disease, the condition of the disease, the difference in medical treatment, and other conditions. However, such an elaborate analysis with the above-mentioned conventional recording and analyzing system requires a change in the program stored in the analyzing unit every time the analyzing and recording methods are changed. For this reason, not only are the number of ambulatory electrocardiographic apparatuses greatly restricted by the number and processing capability of analyzing units, but also minute analysis cannot be carried out speedily and readily. Moreover, it is desired to reduce the size and weight of electrocardiographic apparatus because these apparatuses are carried by respective subjects at all times.